Let's be clear though...the Fractal (and pretty much all guitar modelers) specific purpose is tube emulation. While I certainly understand how analog circuit differences result in different sounds, there is very little in modern music in terms of truly unique to the point of being iconic bass tones outside some of the heaviest genres, we're talking clean tones and not what the typical guitarist calls clean, really and truly clean. While I certainly appreciate a bassist's appreciation of the differences between systems, just like with guitar amps, so much of that is impacted by the speaker choice where again for quite some time many bassists have been running full range (or at least fuller range than guitar cabs) systems. I imagine using the JC120 model and swapping/tuning the EQ and some of the compression characteristics one is going to be able to get very, very close to many of the solid state modern bass amp tones.
To be clear, I'm all for anything added to the Fractal model list which helps anyone achieve their goals. Perhaps just being selfish here, I believe bassist's are probably a very small fraction of Fractal users.